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Kongens Lyngby, Denmark

Seitz S.,Physikalisch - Technische Bundesanstalt | Spitzer P.,Physikalisch - Technische Bundesanstalt | Durbiano F.,INRIM - Istituto Nazionale di Ricerca Metrologica | Jensen H.,Danish Fundamental Metrology Ltd.
20th IMEKO World Congress 2012 | Year: 2012

This work introduces the European Metrology Research Project on the SI traceability of electrolytic conductivity measurements in bioethanol. As a first step to this aim secondary conductivity measurements have been performed to characterise reproducibility, stability, measurement uncertainty and the significance of the measurement results. The standard measurement uncertainty is in the order of 0.3 %. Two samples from different sources show significantly different conductivity values. The results indicate that conductivity is an appropriate quality indicator for bioethanol. Copyright © (2012) by the International Measurement Federation (IMEKO).


Ferreira D.D.M.,Technical University of Denmark | Jakobsen A.C.,Technical University of Denmark | Christensen F.E.,Technical University of Denmark | Shortt B.,European Space Agency | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

We present description and results of the test campaign performed on Silicon Pore Optics (SPO) samples to be used on the ATHENA mission. We perform a pre-coating characterization of the substrates using Atomic Force Microscopy (AFM), X-ray Re ectometry (XRR) and scatter measurements. X-ray tests at DTU Space and correlation between measured roughness and pre-coating characterization are reported. For coating development, a layer of Cr was applied underneath the Ir/B4C bi-layer with the goal of reducing stress, and the use of N2 during the coating process was tested in order to reduce the surface roughness in the coatings. Both processes show promising results. Measurements of the coatings were carried out at the 8 keV X-ray facility at DTU Space and with synchrotron radiation in the laboratory of PTB at BESSY II to determine re ectivity at the grazing incidence angles and energies of ATHENA. Coating development also included a W/Si multilayer coating. We present preliminary results on X-ray Re ectometry and Cross-sectional Transmission Electron Microscopy (TEM) of the W/Si multilayer. © 2012 SPIE.


Feidenhans'L N.A.,Danish Fundamental Metrology Ltd. | Feidenhans'L N.A.,Technical University of Denmark | Hansen P.-E.,Danish Fundamental Metrology Ltd. | Pilny L.,Technical University of Denmark | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

We report a correlation between the scattering value "Aq" and the ISO standardized roughness parameter Rq. The Aq value is a measure for surface smoothness, and can easily be determined from an optical scattering measurement. The correlation equation extrapolates the Aq value from a narrow measurement range of ±16° from specular to a broader range of ±80°, corresponding to spatial surface wavelengths of 0.8 μm to 25 μm, and converts the Aq value to the Rq value for the surface. Furthermore, we present an investigation of the changes in scattering intensities, when a surface is covered with a thin liquid film. It is shown that the changes in the angular scattering intensities can be compensated for the liquid film, using empirically determined relations. This allows a restoration of the "truea" scattering intensities which would be measured from a corresponding clean surface. The compensated scattering intensities provide Aq values within 5.7 % ± 6.1 % compared to the measurements on clean surfaces. © 2015 SPIE.

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